There is proposed a navigation system having a voice recognition apparatus built therein to allow voice recognition of voice from a user so that an address may be input. When such a navigation system is used in an area like Europe, a language that is set as a language used in the navigation system (hereinafter referred to as a “system-set language”) is different from a language expressing a destination. For example, in a case in which a user is an English and a destination of an address is in Germany, it is expected that a system-set language is English and a language expressing a destination is German.
Here, phonemes (equivalent to phonetic symbols) for a place name for performing voice recognition of the place name are provided by a map-making company, which are typically phonemes in a language mainly used in an area of the place name. For example, German phonemes are used as phonemes for a name of a place in Germany. Accordingly, when a language expressing a destination is German, it is desirable in terms of efficiency to use a voice recognition dictionary containing German phonemes provided by a map-making company, and a voice recognition engine for German corresponding to the dictionary.
On the other hand, it is common that a native language of a user is used as a system-set language. Accordingly, when the system-set language is English, it is desirable to use a voice recognition engine for English.
Therefore, in a case in which the system-set language is English and the language expressing a destination is German, a voice recognition dictionary desirable for the language expressing a destination would be different from a voice recognition dictionary desirable for the system-set language.
However, as some of the phonemes (pronunciation) contained in one of English and German languages are not contained in the other of the languages, there has been a problem that a voice recognition engine for one of English and German languages may not handle the phonemes for the other of the languages.
In order to solve this problem, there is proposed a technique using a voice recognition dictionary in which a phoneme a in a language A is associated with one in phonemes b of a language B that is identical or most similar to the phoneme a (e.g., Patent Document 1). Using such a voice recognition dictionary allows phonemes in the language A to be substituted for phonemes in the language B to perform voice recognition with the voice recognition engine in the language B. Hereinafter, in a voice recognition dictionary, associating phonemes in one language with phonemes in a different language is also referred to as “phoneme mapping”.